1. Technical Field
This disclosure relates to gas turbine engine fan blades in general, and to a hybrid fan blades utilizing composite materials in particular.
2. Background Information
Lightweight fan blades such as hybrid fan blades have been developed to reduce weight, centrifugal forces and inertial stress and strain in gas turbine engines. Some fan blades include a unitary hollow metallic airfoil portion formed by casting, forging and other forming techniques followed by milling to final dimensions. Other fan blades include metallic leading edge, trailing edge, and tip portion, independent of one another, fixed to a composite body. The metallic leading and trailing edges are bonded to the composite airfoil to provide erosion and impact resistance. The metallic cap is bonded to the tip of the composite airfoil to provide rubbing resistance. Both the first and the second approaches typically result in a weight reduction over a traditional titanium solid fan blade, but dramatically increase the cost of the fan blade.
Advancements in gas turbine engines have increased the need for fan blades having greater weight reductions (e.g. weight reductions of 40% or higher). Consequently, there is a need for a lightweight fan blade that is not cost prohibitive.